V. FIRST (K) PERFECT SYSTEM (FIRST PERFECT AND PLUPERFECT ACTIVE) 555
The stem of the first perfect is formed by adding -κα to the reduplicated verb-stem. λέ-λυ-κα
a. The κ-perfect is later in origin than the second perfect and seems to have started from verb-stems in -κ, as ἔ-οικ-α (= ϝέ-ϝοικ-α) from εἴκω
Hom. δείδω (used as a present) is for δε-δϝο (ι glide)-α. δειδ- was written on account of the metre when ϝ was lost. Hom. δέδια is for δε-δ (ϝ) ι-α with the weak root that is used in δέδιμεν. See cross703 D.556
The first perfect is formed from verb-stems ending in a vowel, a liquid, or a dental stop (τ, δ, θ).557
Vowel Verbs.—Vowel verbs lengthen the final vowel (if short) before -κα, as τι_μά-ω
1. Hom. has the κ-perfect only in verbs with vowel verb-stems. Of these some have the second perfect in -α, particularly in participles. Thus κεκμηώς, Attic κεκμηκώς (κάμ-ν-ω
2. In some dialects a present was derived from the perfect stem; as Hom. ἀνώγω, Theocr. δεδοίκω, πεφύ_κει (in the 2 perf.: Theocr. πεπόνθω). Inf. τεθνάκην (Aeol.), part. κεκλήγοντες (Hom.), πεφρί_κων (Pind.).
3. From μέμηκα (μηκάομαι
Liquid Verbs.—Many liquid verbs have no perfect or employ the second perfect. Examples of the regular formation are φαίνω (φαν-)
a. Some liquid verbs drop ν; as κέκρικα, κέκλικα from κρί_νω (κριν-)
b. Monosyllabic stems change ε to α; as ἔσταλκα, ἔφθαρκα from στέλλω (στελ-)
N. For α we expect ο; α is derived from the middle (ἔσταλμαι, ἔφθαρμαι).
c. All stems in μ and many others add ε ( cross485); as νέμω (νεμ-ε-), distribute νενέμηκα, μέλω (μελ-ε-)
d. Many liquid verbs suffer metathesis ( cross492) and thus get the form of vowel verbs; as βάλλω (βαλ-)
Stop Verbs.—Dental stems drop τ, δ, θ before -κα; as πείθω (πιθ-, πειθ-, ποιθ-)
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].